Field of Technology
The present invention relates generally to sensing usage of reusable cassettes/packs for surgical devices to determine if cassette/pack usage has reached a maximum number.
Description of the Background
The optical elements of the eye include both a cornea (at the front of the eye) and a lens within the eye. The lens and cornea work together to focus light onto the retina at the back of the eye. The lens also changes in shape, adjusting the focus of the eye to vary between viewing near objects and far objects. The lens is found just behind the pupil and within a capsular bag, the capsular bag being a thin, relatively delicate structure which separates the eye into anterior and posterior chambers.
With age, clouding of the lens or cataracts is fairly common. Cataracts may form in the hard central nucleus of the lens, in the softer peripheral cortical portion of the lens, or at the back of the lens near the capsular bag. Cataracts can be treated by the replacement of the cloudy lens with an artificial lens. Phacoemulsification systems often use ultrasound energy to fragment the lens and aspirate the lens material from within the capsular bag. This may allow the capsular bag to be used for positioning of the artificial lens, and maintains the separation between the anterior portion of the eye and the vitreous humor in the posterior chamber of the eye.
During cataract surgery and other therapies of the eye, accurate control over the volume of fluid within the eye is highly beneficial. For example, while ultrasound energy breaks up the lens and allows it to be drawn into a treatment probe with an aspiration flow, a corresponding irrigation flow may be introduced into the eye so that the total volume of fluid in the eye does not change excessively. If the total volume of fluid in the eye is allowed to get too low at any time during the procedure, the eye may collapse and cause significant tissue damage. Similarly, excessive pressure within the eye may strain and injure tissues of the eye.
While a variety of specific fluid transport mechanisms have been used in phacoemulsification and other treatment systems for the eyes, aspiration flow systems can generally be classified in two categories: 1) volumetric-based aspiration flow systems using positive displacement pumps (e.g. peristaltic); and 2) vacuum-based aspiration systems using a vacuum source, typically applied to the aspiration flow through an air-liquid interface within a reservoir (e.g. Venturi). Both systems may be incorporated into one treatment system and/or cassette. Cassette (“pack”) systems may be used to couple peristaltic pump drive rotors and/or vacuum systems of the surgical consoles to an eye treatment handpiece, with the flow network conduit of the cassette being disposable to avoid cross-contamination between different patients.
The disposable cassettes provide protection for each patient by avoiding cross-contamination between different patients. The disposable cassettes may be single-use, where the cassette is disposed after one use, or multi-use, where cassettes are reused after proper sterilization (e.g., autoclaving). In the case of multi-use phacoemulsification (“phaco”) surgical packs, there is a maximum number of times a multi-use pack can or should be reused, as the pack quality deteriorates after certain amounts of usage and autoclave. Systems incorporating barcodes, such as one described in U.S. Pat. No. 6,036,458 to Cole et al., titled “Automated Phaco Pack Bar Code Reader Identification” issued Mar. 14, 2000, which is incorporated by reference herein, have been proposed to track usage and disposal of cartridges. However, such systems are not effective in accurately and consistently tracking usage for disposal purposes. Such systems are also not effective in accurately and consistently tracking a pack used on more than one system or machine. A mechanism to track how many times the cassette has been used is needed to ensure that it will not be used more than the recommended maximum number of times.